Solid ink jet printers can use opposing nipped rollers wherein at least one is conformable to form a nip in which pressure and optionally heat are used to partially or fully melt the ink to reduce the height of the ink and spread the ink. A spreader may be necessary to enhance the image quality of the print. Spreader stations described in the current art are basically comprised of pairs of opposing rollers, where at least one is conformable, form a nip, similar to those used in fusers in the field of electrophotography. Most high speed commercial inkjet printers use continuous paper rolls, instead of paper sheets. One performance concern of the spreader station used in this application is wrinkles in the paper prints.
Print wrinkles and image artifacts are caused by stresses built up in the web as it passes through the fuser or spreader nip. The stresses are caused by variations in the image thickness, variations in web thickness caused by variations in relative humidity, differential moisture absorption by the web and variations in the outside diameter or conformable layer thickness of the spreader or pressure rollers caused by differential axial temperature or manufacturing tolerances. In a sheet fed application, these stresses are eliminated as each sheet exits the fuser or spreader. In a web application, the stresses are not eliminated for a very long time, given many paper rolls are 20,000 feet long, or more. Thus, paper wrinkles are a large concern in a web-fed solid inkjet printer.